Recently, technology that uses a remote phosphor to reduce a loss caused by return light has attracted attention. In a typical remote phosphor, an LED chip is disposed on a reflecting plate comprising a specular reflection plate or a diffuse reflection plate, over which a domed fluorescent layer is formed. The fluorescent layer is located at a distance from the LED chip so that the return light to the LED chip is reduced.
However, if the loss caused by return light is reduced by the remote phosphor in this manner, the size increase of the whole lighting device including the fluorescent layer and the LED is inevitable. For example, when the dimension of the LED chip is 1 mm, the size of the whole lighting device is about 1 to 2 cm.